scholarly journals Superfluids, Fluctuations and Disorder

2019 ◽  
Vol 9 (7) ◽  
pp. 1498 ◽  
Author(s):  
Alberto Cappellaro ◽  
Luca Salasnich
Keyword(s):  
Functional Integration ◽  
External Potential ◽  
Quenched Disorder ◽  
Superfluid Phase ◽  
Energy Landscapes ◽  
Replica Trick ◽  
Symmetry Phase ◽  
Integration Techniques ◽  
Bosonic Atoms ◽  
Disordered Energy

We present a field-theory description of ultracold bosonic atoms in the presence of a disordered external potential. By means of functional integration techniques, we aim to investigate and review the interplay between disordered energy landscapes and fluctuations, both thermal and quantum ones. Within the broken-symmetry phase, up to the Gaussian level of approximation, the disorder contribution crucially modifies both the condensate depletion and the superfluid response. Remarkably, it is found that the ordered (i.e., superfluid) phase can be destroyed also in regimes where the random external potential is suitable for a perturbative analysis. We analyze the simplest case of quenched disorder and then we move to present the implementation of the replica trick for ultracold bosonic systems. In both cases, we discuss strengths and limitations of the reviewed approach, paying specific attention to possible extensions and the most recent experimental outputs.

scholarly journals GROUND STATE PROPERTIES OF THE NELSON HAMILTONIAN: A GIBBS MEASURE-BASED APPROACH

2002 ◽  
Vol 14 (02) ◽  
pp. 173-198 ◽  
Author(s):  
VOLKER BETZ ◽  
FUMIO HIROSHIMA ◽  
JÓZSEF LŐRINCZI ◽  
ROBERT A. MINLOS ◽  
HERBERT SPOHN
Keyword(s):  
Gibbs Measure ◽  
Ground State ◽  
Momentum Space ◽  
Quantum Particle ◽  
Functional Integration ◽  
External Potential ◽  
Space Distribution ◽  
Position Space ◽  
Nelson Model ◽  
Integration Techniques

The Nelson model describes a quantum particle coupled to a scalar Bose field. We study properties of its ground state through functional integration techniques in case the particle is confined by an external potential. We obtain bounds on the average and the variance of the Bose field both in position and momentum space, on the distribution of the number of bosons, and on the position space distribution of the particle.

scholarly journals Dynamics of fluids in quenched-random potential energy landscapes: a mode-coupling theory approach

Soft Matter ◽  
2017 ◽  
Vol 13 (31) ◽  
pp. 5283-5297 ◽  
Author(s):  
Thomas Konincks ◽  
Vincent Krakoviack
Keyword(s):  
Potential Energy ◽  
Mode Coupling ◽  
Random Potential ◽  
Quenched Disorder ◽  
Theory Approach ◽  
Coupling Theory ◽  
Mode Coupling Theory ◽  
Energy Landscapes ◽  
Random Energy ◽  
Potential Energy Landscapes

Interplay of crowding and quenched disorder in the dynamics of fluids in random energy landscapes according to a mode-coupling theory.

Calculations of Eigenvalues in Functional Nonlinear Spinor Theory

1972 ◽  
Vol 27 (7) ◽  
pp. 1042-1057
Author(s):  
K Dammeier
Keyword(s):  
Differential Equation ◽  
Functional Integration ◽  
Eigenvalue Equation ◽  
Fermion Propagator ◽  
Nonlinear Spinor ◽  
Third Order ◽  
Spinor Theory ◽  
Self Consistent ◽  
Integration Techniques ◽  
Modified Theory

Abstract A differential equation of third order for spinor potentials is proposed, that modifies the dynamics of the nonlinear spinor theory. We derive a symmetrical eigenvalue equation using functional integration techniques. This equation and a momentum symmetrized equation - a simplified form of the mass eigenvalue equation proposed by Stumpf - are applied to calculate mass eigenvalues. By a special combination of both methods it is possible to weaken the regulari-zation dipole in Heisenberg's theory and thereby produce better boson masses. Finally, the modified theory allows a self-consistent calculation of the fermion propagator

scholarly journals Intrinsically Disordered Energy Landscapes

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Yassmine Chebaro ◽  
Andrew J. Ballard ◽  
Debayan Chakraborty ◽  
David J. Wales
Keyword(s):  
Energy Landscapes ◽  
Intrinsically Disordered ◽  
Disordered Energy

PHAX-SCAN: Functional integration of a Scanning Electron Microscope and an energy-dispersive x-ray analyser

1989 ◽  
Vol 47 ◽  
pp. 56-57
Author(s):  
Marc H. Peeters ◽  
Max T. Otten
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
High Speed ◽  
High Performance ◽  
Functional Integration ◽  
Energy Dispersive ◽  
X Rays ◽  
X Ray ◽  
High Speed Analysis ◽  
Scanning Electron

Over the past decades, the combination of energy-dispersive analysis of X-rays and scanning electron microscopy has proved to be a powerful tool for fast and reliable elemental characterization of a large variety of specimens. The technique has evolved rapidly from a purely qualitative characterization method to a reliable quantitative way of analysis. In the last 5 years, an increasing need for automation is observed, whereby energy-dispersive analysers control the beam and stage movement of the scanning electron microscope in order to collect digital X-ray images and perform unattended point analysis over multiple locations.The Philips High-speed Analysis of X-rays system (PHAX-Scan) makes use of the high performance dual-processor structure of the EDAX PV9900 analyser and the databus structure of the Philips series 500 scanning electron microscope to provide a highly automated, user-friendly and extremely fast microanalysis system. The software that runs on the hardware described above was specifically designed to provide the ultimate attainable speed on the system.

Site-Specific Protein Covalent Attachment to Nanotubes and Its Electronic Impact on Single Molecule Function

2019 ◽  
Author(s):  
Adam Beachey ◽  
Harley Worthy ◽  
William David Jamieson ◽  
Suzanne Thomas ◽  
Benjamin Bowen ◽  
...  
Keyword(s):  
Single Molecule ◽  
Fluorescent Protein ◽  
Functional Integration ◽  
Attachment Site ◽  
Covalent Attachment ◽  
Great Promise ◽  
Functional Coupling ◽  
Phenyl Azide ◽  
Electronic Impact ◽  
Protein Attachment

<p>Functional integration of proteins with carbon-based nanomaterials such as nanotubes holds great promise in emerging electronic and optoelectronic applications. Control over protein attachment poses a major challenge for consistent and useful device fabrication, especially when utilizing single/few molecule properties. Here, we exploit genetically encoded phenyl azide photochemistry to define the direct covalent attachment of three different proteins, including the fluorescent protein GFP, to carbon nanotube side walls. Single molecule fluorescence revealed that on attachment to SWCNTs GFP’s fluorescence changed in terms of intensity and improved resistance to photobleaching; essentially GFP is fluorescent for much longer on attachment. The site of attachment proved important in terms of electronic impact on GFP function, with the attachment site furthest from the functional center having the larger effect on fluorescence. Our approach provides a versatile and general method for generating intimate protein-CNT hybrid bioconjugates. It can be potentially applied easily to any protein of choice; attachment position and thus interface characteristics with the CNT can easily be changed by simply placing the phenyl azide chemistry at different residues by gene mutagenesis. Thus, our approach will allow consistent construction and modulate functional coupling through changing the protein attachment position.</p>

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